BIRDS OF NORTH AND MIDDLE AMERICA. 597 
very pale rufous-buff or buffy whitish; wing 4040.5, tail 28-29, ex- 
posed culmen 11.5-12. (Western Panam4.) 
Selasphorus ardens, adult male (p. 604). 
Jf. Middle rectrices narrowly edged with cinnamon-rufous, the inner 
webs of lateral rectrices without rufous edging; under tail-coverts 
light cinnamon-rufous or vinaceous-cinnamon; wing 36.5-40 (38.4), 
tail 26.5-28.5 (27.7), exposed culmen 10-11.5 (10.5). (Costa Rica.) 
Selasphorus simoni, adult male (p. 606). 
ce. Throat brilliant metallic orange-red or scarlet; rectrices mostly cinnamon- 
rufous. 
d. Smaller (wing less than 35, tail less than 25, exposed culmen less than 12). 
(Costa Rica and western Panama.) 
Selasphorus scintilla, adult male (p. 607). 
dd. Larger (wing more than 36), tail not less than 25, exposed culmen 15 or 
more. 
e. Back and rump metallic green; rectrices much narrower (the outermost 
much less than 2 wide), the middle pair not notched near tip. (Pacific 
coast from British Columbia to northwestern Mexico.) 
Selasphorus alleni, adult male (p. 609). 
ee. Back and rump cinnamon-rufous; rectrices much broader, the outer- 
most not less than 2 wide, the middle pair notched near tip. (Western 
North America, from Guatemala to Alaska.) 
Selasphorus rufus, adult male (p. 612). 
bb. Pileum brilliant metallic red, like throat. (California to northwestern Mexico.) 
Selasphorus floresii,? adult male (p. 616). 
aa. Throat whitish, usually flecked with dusky, sometimes with a few feathers of 
metallic red or purple. (Adult females.) 
b. Middle rectrices wholly metallic green or else merely edged with cinnamon- 
rufous. 
c. Larger (wing 45.5-52, exposed culmen 17-20); tips of lateral rectrices pure 
WhHItCE oss5..dvie eres eclekie vy x Selasphorus platycercus, adult female (p. 598). 
cc. Smaller (wing 39.5-43. 5, exposed culmen 11-13.5); tips of lateral rectrices 
more or less rufescent. 
Selasphorus flammula (p. 602), Selasphorus torridus (p. 603), Selasphorus 
ardens (p. 605), and Selasphorus simoni (p. 606), adult females. 
bb. Middle rectrices extensively cinnamon-rufous basally. 
ce. Smaller (wing 34-37.5, exposed culmen 11.5~12.5); tips of lateral rectrices 
cinnamon-rufous...........-.-- Selasphorus scintilla, adult female (p. 608). 
ce. Larger (wing 41-45, exposed culmen 17-19); tips of lateral rectrices white. 
d. Lateral rectrices much narrower (not more than 2 mm.); wing 41-42 (41.6); 
tail, 23-26 (24.7)..-...-.-.----- Selasphorus alleni, adult female (p. 610). 
dd. Lateral rectrices broader (more than 3 mm. wide); wing 43-45 (44.4); 
tail 24.5-28 (26.4).............Selasphorus rufus, adult female (p. 612). 
SELASPHORUS PLATYCERCUS (Swainson). 
BROAD-TAILED HUMMING BIRD. 
Adult male-—Above metallic bronze-green or greenish bronze; 
middle pair of rectrices metallic bronze-green (sometimes more 
bluish green); rest of tail dull purplish or bronzy black, the pair 
@ This is undoubtedly a hybrid between Selasphorus alleni and Calypte anna. 
b Before it is possible to give a key showing satisfactorily the differential characters 
of these species, the very careful examination and comparison of a much larger num- 
ber of specimens is necessary. 
